1. Field of the Invention
The present invention relates a rotary switch and more particularly to a waterproof rotary switch that lowers the change of entering of water into the inside of the switch, assuring safety.
2. Description of the Related Art
A switch is a requisite device for controlling the supply of power supply. By means of a power switch, the user can cut off power supply when the power supply is not necessary, preventing a disaster. A power supply control switch can be a normal-close switch that is constantly kept in a close-circuit position and can be operated to switch off the power supply when the power supply is not necessary. Alternatively, a power supply control switch can be a normal-open switch that is constantly kept in an open-circuit status and can be operated to switch on the power supply when the power supply is required. Therefore, regular electric devices are commonly equipped with a power switch for power on/off control. Basically, a power switch obtains power supply by means of electrically connecting two electrodes to close the power circuit. When the two electrodes are disconnected, the power circuit is off.
In addition to accurate conduction and disconduction, safety is an important factor must be taken into account during the use of a power switch. For example, a power switch must prevent electric leakage and eliminate conduction error. For use in certain particular places, such as powder dust floating or high humidity working environment, a power switch must provide a dustproof or waterproof function to prevent short-circuit or rust that may shorten the service life of the switch.
U.S. Pat. No. 7,148,440 B2 discloses a switch structure, entitled “Stackable switch assembly”, which includes a base switch housing having a first switch disposed therein, and including base switch housing surface structure; at least one intermediate switch housing having an other switch disposed therein, the intermediate switch housing including intermediate switch housing surface structure that confronts and cooperates with the base switch housing surface structure to directly attach and mechanically engage the intermediate switch housing to the base switch housing; a cover including cover surface structure for selective positioning in confrontation against, attachment to and engagement with the base switch housing surface structure and the intermediate switch housing surface structure; and an actuator disposed within the base switch housing and the intermediate switch housing for operating the first switch and the other switch.
The stackable switch assembly of U.S. Pat. No. 7,148,440 B2 is used in a gas control valve. When rotating the rotary knob of the gas control valve, the actuator is rotated to squeeze an ignition device (piezoelectric device), causing conduction between the ignition device and the components of one switch of the stackable switch assembly to form a loop and to ignite the gas burner. At the same time, the loop formed of the other switch turns on an indicator light, indicating the burning status of the gas burner. This stackable switch assembly overcomes the inconvenience of a single-loop switch design.
According to the aforesaid stackable switch assembly, the top and bottom sides of the intermediate switch housing are respectively abutted against the cover and the base switch housing. Because the stackable switch assembly is used in a gas burner, for example, a gas range, the boiled fluid of the cooking food may overflow and drop to the inside of the gas control valve and the internal components of the switches of the stackable switch assembly when the user uses the gas range to cook food, or water may leak into the inside of the gas control valve and the internal components of the switches of the stackable switch assembly when the user is cleaning the gas range with water. When a fluid or water enters the switches of the stackable switch assembly, the internal components of the switches of the stackable switch assembly will be wetted, causing a short circuit to turn on the indicator light erroneously as the actuator is not operated.
Therefore, it is desirable to provide a waterproof switch that eliminates the aforesaid problem.